Switzerland’s extreme summer exposes gaps in heatwave preparedness

Three consecutive tropical nights in September have brought Switzerland’s heat problem into the early autumn. Locarno-Monti recorded minimum temperatures of 20.7°C on Saturday morning, 21.2°C on Sunday and 20.9°C on Monday, MeteoSwiss told Keystone-SDA on September 8, 2026.

The readings are significant because a tropical night is defined by a minimum temperature of at least 20°C. Since records began at the station in 1935, Locarno had registered only nine tropical nights in September. Lugano has recorded 11 since measurements began there in 1864.

The latest sequence followed a summer in which Locarno recorded 57 nights above 20°C. Lugano recorded 54, according to the figures cited by Keystone-SDA. A high pressure system was expected to keep Switzerland under warm conditions for the following ten days, with some rain forecast south of the Alps.

Night-time heat matters because it limits the body’s ability to recover from daytime exposure. The burden falls hardest on older people, those with chronic illness, pregnant women and young children. It also keeps homes, workplaces and care facilities hot after sunset, when many residents expect relief.

Switzerland’s summer temperatures ran 5°C to 10°C above the long term average on many days. The country’s summer is likely to become the hottest ever recorded, according to the Swissinfo report published on September 9.

In several places, temperatures approached 40°C. Heat alerts remained in force for weeks, turning what once appeared to be a short seasonal episode into a sustained public health exposure. High temperatures can cause dehydration, exhaustion and heatstroke. They can also worsen existing medical conditions and, in severe cases, cause death.

Ana Maria Vicedo Cabrera, an environmental epidemiologist and professor at the University of Bern, said Switzerland has been slower to adapt than countries where hot weather is more familiar. “Spain is certainly hotter than Switzerland, but we have become accustomed to living with these conditions. In Switzerland, we have not yet adapted,” she told Swissinfo.

The country’s housing stock adds pressure. Many homes lack air conditioning and are not designed to shed heat efficiently. Tropical nights intensify that problem by extending exposure beyond working hours and into sleep. Repeated poor sleep can reduce concentration, physical resilience and the ability to cope with another hot day.

Swiss cities are building local responses, but protection still depends heavily on where a person lives. Ticino adopted heatwave tools and an action plan in 2004, while Geneva followed in 2007. Their measures include early warning systems, coordination between social and healthcare services, and access to cooler public spaces.

Geneva has offered residents aged 65 and over free morning access to two municipal swimming pools during the hottest days. In the afternoons, three air-conditioned cinemas have provided another refuge. Around 8,600 people used these services between June 18 and August 5, 2026.

The city has also promoted green spaces and other cooler locations. Climate shelters are especially relevant in Switzerland, where air conditioning is uncommon in homes. They can provide relief for people who cannot cool their apartments, including older residents living alone.

Yet the measures remain uneven. Some municipalities have detailed alert chains and outreach programmes. Others rely mainly on public warnings. The Swissinfo report says the effectiveness of several interventions is still being assessed, making reliable evaluation and common standards important as heat events become more frequent across the country.